Bunch of space news today

[n2doc]

Youngest Extra-Solar Planet Discovered Around Solar-Type Star
ScienceDaily (Feb. 19, 2010) — Astronomers have discovered the youngest extra-solar planet around a solar-type star, named BD+20 1790b.

The giant planet, six-times the mass of Jupiter, is only 35 million years old. It orbits a young active central star at a distance closer than Mercury orbits the Sun. Young stars are usually excluded from planet searches because they have intense magnetic fields that generate a range of phenomena known collectively as stellar activity, including flares and spots. This activity can mimic the presence of a companion and so can make extremely difficult to disentangle the signals of planets and activity.
University of Hertfordshire astronomers, Dr Maria Cruz Gálvez-Ortiz and Dr John Barnes, are part of the international collaboration that made the discovery.
http://www.sciencedaily.com/releases/2010/02/100218092752.htm

Red Dwarf-Red Giant Binary Pair of Stars Found
ScienceDaily (Feb. 19, 2010) — A binary pair of red stars, one giant one dwarf, has been discovered by a collaboration of astrophysicists from the University of Hertfordshire and The Chinese Academy of Sciences.
The discovery, which is due to be published in the Monthly Notices of the Royal Astronomical Society later this month reports that the researchers have identified an ultra-cool companion to the bright red giant star Eta Cancri, using the UK Infrared Telescope in Hawaii and the Sloan Digital Sky Survey in New Mexico.
Ultra-cool dwarfs are star-like objects, but with surface temperatures much cooler than normal stars -- less than 2000 degrees (compare this to the Sun's temperature of about 6000 degrees). Exotic dusty clouds condense out at such ultra-cool temperatures, leading to objects that are hybrid in nature -- with characteristics of both stars and giant planets like Jupiter.
Red giant stars are much bigger and more massive, and are evolving towards the end of their life (our Sun will become a red giant in about 5 billion years). But as they evolve towards their demise they can reveal information about their age and chemical composition.
http://www.sciencedaily.com/releases/2010/02/100216221147.htm


No Place to Hide: Missing Primitive Stars Outside Milky Way Uncovered
ScienceDaily (Feb. 18, 2010) — After years of successful concealment, the most primitive stars outside our Milky Way galaxy have finally been unmasked. New observations using ESO's Very Large Telescope have been used to solve an important astrophysical puzzle concerning the oldest stars in our galactic neighbourhood -- which is crucial for our understanding of the earliest stars in the Universe.

The Fornax dwarf galaxy is one of our Milky Way’s neighbouring dwarf galaxies. The Milky Way is, like all large galaxies, thought to have formed from smaller galaxies in the early days of the Universe. These small galaxies should also contain many very old stars, just as the Milky Way does, and a team of astronomers has now shown that this is indeed the case. This image was composed from data from the Digitized Sky Survey 2. (Credit: ESO/Digitized Sky Survey 2)
"We have, in effect, found a flaw in the forensic methods used until now," says Else Starkenburg, lead author of the paper reporting the study. "Our improved approach allows us to uncover the primitive stars hidden among all the other, more common stars."
Primitive stars are thought to have formed from material forged shortly after the Big Bang, 13.7 billion years ago. They typically have less than one thousandth the amount of chemical elements heavier than hydrogen and helium found in the Sun and are called "extremely metal-poor stars" <1>. They belong to one of the first generations of stars in the nearby Universe. Such stars are extremely rare and mainly observed in the Milky Way.
Cosmologists think that larger galaxies like the Milky Way formed from the merger of smaller galaxies. Our Milky Way's population of extremely metal-poor or "primitive" stars should already have been present in the dwarf galaxies from which it formed, and similar populations should be present in other dwarf galaxies. "So far, evidence for them has been scarce," says co-author Giuseppina Battaglia. "Large surveys conducted in the last few years kept showing that the most ancient populations of stars in the Milky Way and dwarf galaxies did not match, which was not at all expected from cosmological models."

http://www.sciencedaily.com/releases/2010/02/100217093251.htm

Jets of Particles Streaming from Black Holes in Far-Away Galaxies Different Than Previously Thought
ScienceDaily (Feb. 18, 2010) — Jets of particles streaming from black holes in far-away galaxies operate differently than previously thought, according to a study published February 17 in Nature. The new study reveals that most of the jet's light -- gamma rays, the universe's most energetic form of light -- is created much farther from the black hole than expected and suggests a more complex shape for the jet.

The research was led by scientists at the Kavli Institute for Particle Astrophysics and Cosmology, jointly located at the Department of Energy's SLAC National Accelerator Laboratory and Stanford University, with participation from scientists from around the world. The study included data from more than 20 telescopes including the Fermi Gamma-ray Space Telescope and KANATA telescope.
High above the flat Milky Way galaxy, bright galaxies called blazars dominate the gamma-ray sky, discrete spots on the dark backdrop of the universe. As nearby matter falls into the black hole at the center of a blazar, "feeding" the black hole, it sprays some of this energy back out into the universe as a jet of particles.
"As the universe's biggest accelerators, blazar jets are important to understand," said KIPAC Research Fellow Masaaki Hayashida, who serves as corresponding author on the paper with KIPAC Astrophysicist Greg Madejski. "But how they are produced and how they are structured is not well understood. We're still looking to understand the basics."
http://www.sciencedaily.com/releases/2010/02/100217142635.htm